Process of making 1-4-diarylamino-5-8-dihydroxyanthraquinone



Patented May 1929.

UNITED STATES,

KLAUS WEINZAND, -01? COLOGNE-FLITTABD, STUFF CORPORATION, OF NEW YORK,

GERMANY, ASSIGNOB TO GRASSELLI DYE- N. Y., A CORPORATION OF DELAWARE.

PROCESS OF MAKING 14 D1ABYLmINO-5-8-DIHYDROXYANTHRAQUmONE. I

No Drawing. Application filed June 26, 1926, Serial No. 118,847, and in Germany July 8, 1925.

My invention consists in 1-4-diarylamino- 5-8-dihydroxy-anthraquinones and processes of making thesame. a

It is well known that hydroxy-anthraquinone compounds react with arylamines in presence of condensing agents such as boric acid, hydrochloric acid etc., to form arylamino-anthraquinones. Better results are obtained if leuco-hydroxy-anthraquinonesare reacted upon with arylamincs and condensing agents, these leuco-arylamino-anthraquinones are then easily oxidized to the arylamino-anthraquinones. This oxidation already takes place, at least to a certain ex tent, if air, or the parent hydroxy-anthra quinones, are present during the condensation, or can be effected subsequent to the condensation.

of 1-4-di-p-to1uido-5 They are valuable intermediates for the production of dyestufis.

The following examples will further illustrate my invention, the parts being by weight:

Example 1.4 parts 1-4-5 8-leuco-tetrahydroxy-anthraquinone are. dissolved in 40 parts p-toluidine and heated to 100 C. 1 part arsenic acid is now introduced; after 15 minutes heating 0.8 parts boric acid are added, the reaction starts immediately and the melt is heated for 1 to 1 hours. The melt is worked up as usual and a good yield 8 dihydroxy anthraquinone of the formula:

on NEG-CH;

I have found that 1-4-diarylamino-5-8-di V 'hydroxy-anthraquinone' is produced in a very convenientlnanner if the condensation of leuc0-1-4-5-8-tetra-hydroxy-anthraquin one with an arylamine is effected in the presence of arsenic acid, which simultaneously with the condensation efiects the oxidation of the intermediately formed leuco-compound. The yields of pure products are nearly quantitative and the reaction proceeds at a relatively low temperature of around 100 C- and evenin practically anhydrous conditions.

This is of particular interest inasmuch as the usual condensing agents produce li-diarylamino 5 8 dihydroxy anthraquinones from the leuco-tetra-hydroxy-anthraquinone andarylamines only with very unsatisfac tory yields and purity. Experiments made in this direction haveshown that by carrying out the reaction in the old and well known manner mostly tarry products with very little 1-4-diarylamino-5-8 dihydroxy anthraquinone are obtained.

The novel 1-4diarylamino-5-8-dihydroxyanthraquinones are of the general formula:

CO I a NH-Aryl NITOC H: is obtained.

0.8 parts boric acid are added. The reaction starts immediately and the melt is heated for 1 to 1 hours. The melt is worked up as usual and a good yield of 1-4-di-ani1ido-5-8- dihydroxy-anthraquinone of the formula Lon NHO H -NH is obtained. v

I- claim: 111 The process of making 1-4-diarylamino- 5-8-dihIydroxy-anthraquinones which con1- prises eating under practically anhydrous conditions leuco 1 -4 -5 8-tetra-hydroxy-anthraquinone with an arylamine in the-presence of arsenic acid and a condensing agent. 2. The process of making 1-4-diarylamin'o- 5-8-dihydroxy-anthraquinone which com- C. 1 part arsenic prises heating to about 100 tically anhydrous conditions tetro-hydroxy-anthraquinone C. under pracwith an arylamine in the presence of arsenic acid and 5 boricacid.

3. The process of making 1-4-di-p-to1uido- 5 8 dihydroxy anthraqumone which comprises heating to about 100 C. under pracleuco -l-4-5- A whereof I ha e hereunto set my hand.

KLAUS WEINAND. 

